The the wires to the brake switches on my '80 are soldered in, as should yours be.
To remove the switch from the brake lever, remove the screw at the lever's pivot point and remove the lever. The switch itself should slide out now that the lever isn't in the way.
The switch itself comprises of 2 copper contact leaves, a piston, a spring and a retainer. The wires should be soldered to the 2 copper leaves. To be able to resolder the wires on, you'll have to completely disassemble the switch. This in itself may be too much trouble for you, but if you need help re'assemling the switch, lemme know. =)